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X-ray data from NASA's MESSENGER probe points to high levels of magnesium and sulfur on the surface of the planet Mercury, suggesting its makeup is far different from that of other planets, scientists say.

The unmanned orbiter has been beaming back data from the first planet for a year and a half. Readings from its X-ray spectrometer point to a planet whose northern volcanic plains formed through upwellings of rocks more exotic than those often found on the Earth, the Moon or Mars, said Shoshana Weider, a researcher at the Carnegie Institution of Washington.

"Before this MESSENGER mission, a lot of people assumed it was very like the Moon -- it's dark, it's grey," Weider said. But while the Moon's surface formed when light materials floated to the top of an ocean of molten rock, the low level of calcium on Mercury indicates that didn't happen there.

"This gives us clues to the kind of precursor materials that accreted to form Mercury, in an extremely oxygen-poor environment," Weider said.

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So, because of the high levels of magnesium and sulfur on the surface of Mercury we can speculate that it didn't originate with the rest of the planets of our solar system. Rogue planet that got sucked into the orbit of the sun and has been chilling here ever sense... I wonder where it came from. *hmmmmm*